The most common type of cement-like material is one which is reinforced with asbestos. This material is used in the preparation of, for example, pipes, tiles, wall coverings, vases, house, roof and chimney coverings, etc.
Asbestos-containing cement-like materials are relatively strong even at reduced thickness. The conventional asbestos containing cement-like substrates, however, have a relatively low shock resistance and are likely to break easily on impact with stone. This characteristic is particularly important when the asbestos-containing cement-like substrate is used for the preparation of pipes, tiles, wall coverings, etc.
It has already been suggested to increase the strength of the cement-like material by increasing the asbestos content. However, this method produces only a small increase in strength and is not recommended because of the expense and waste of material resulting from the increased amount of asbestos.
It has also been proposed to use natural or synthetic fibers to reinforce the cement matrix. If natural fibers such as cellulose, cotton and silk as well as man-made fibers such as polyamide, polyester and polypropylene fibers are added, some additional strength is achieved. However, not enough additional strength is achieved to consider this method a success.
Relatively good results are obtained by the addition of glass fibers to the cement-like substrate. In particular, an alkali-resistant glass fiber (for example, see Japanese Laid-Open Specification 104, 918/1974) produces the best results but is disadvantageous because of the high cost involved. Additionally, extensive research has proven that the use of glass fibers results in reduced strength of the product after a relatively short time.
Inorganic and organic fibers have also been used to reinforce cement-like materials. Japanese Laid-Open specification 104,917/1974 teaches that reinforced cement products can be prepared using mixtures of glass fiber and polyvinyl alcohol fibers. However, these products are not ideal, particularly because of their inferior bending strength.